[RFC PATCH 04/11] powerpc/svm: Convert SWIOTLB buffers to shared memory

From: Thiago Jung Bauermann
Date: Fri Aug 24 2018 - 12:26:18 EST


From: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>

Hook the shared memory conversion functions into the ARCH_HAS_MEM_ENCRYPT
framework and call swiotlb_update_mem_attributes() to convert SWIOTLB's
buffers to shared memory.

Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx>
---
arch/powerpc/Kconfig | 4 ++++
arch/powerpc/include/asm/mem_encrypt.h | 19 +++++++++++++++++++
arch/powerpc/kernel/svm.c | 34 ++++++++++++++++++++++++++++++++++
3 files changed, 57 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 90f73d15f58a..1466d1234723 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -440,12 +440,16 @@ config MATH_EMULATION_HW_UNIMPLEMENTED

endchoice

+config ARCH_HAS_MEM_ENCRYPT
+ def_bool n
+
config PPC_SVM
bool "Secure virtual machine (SVM) support for POWERPC"
default n
depends on PPC_PSERIES
select DMA_DIRECT_OPS
select SWIOTLB
+ select ARCH_HAS_MEM_ENCRYPT
help
Support secure guests on POWERPC. There are certain POWER platforms
which support secure guests with the help of an Ultravisor executing
diff --git a/arch/powerpc/include/asm/mem_encrypt.h b/arch/powerpc/include/asm/mem_encrypt.h
new file mode 100644
index 000000000000..2b6e37ea446c
--- /dev/null
+++ b/arch/powerpc/include/asm/mem_encrypt.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * SVM helper functions
+ *
+ * Copyright 2018 IBM Corporation
+ */
+
+#ifndef _ASM_POWERPC_MEM_ENCRYPT_H
+#define _ASM_POWERPC_MEM_ENCRYPT_H
+
+#define sme_me_mask 0ULL
+
+static inline bool sme_active(void) { return false; }
+static inline bool sev_active(void) { return false; }
+
+int set_memory_encrypted(unsigned long addr, int numpages);
+int set_memory_decrypted(unsigned long addr, int numpages);
+
+#endif /* _ASM_POWERPC_MEM_ENCRYPT_H */
diff --git a/arch/powerpc/kernel/svm.c b/arch/powerpc/kernel/svm.c
index 37437cf92df5..eab2a64d8643 100644
--- a/arch/powerpc/kernel/svm.c
+++ b/arch/powerpc/kernel/svm.c
@@ -7,6 +7,20 @@
*/

#include <linux/mm.h>
+#include <linux/swiotlb.h>
+#include <asm/machdep.h>
+#include <asm/svm.h>
+
+static int __init init_svm(void)
+{
+ if (!is_svm_platform())
+ return 0;
+
+ swiotlb_update_mem_attributes();
+
+ return 0;
+}
+machine_early_initcall(pseries, init_svm);

void mem_convert_shared(unsigned long pfn, unsigned long npages)
{
@@ -31,3 +45,23 @@ void mem_convert_secure(unsigned long pfn, unsigned long npages)
* ucall_convert_secure(paddr, size)
*/
}
+
+int set_memory_encrypted(unsigned long addr, int numpages)
+{
+ if (!PAGE_ALIGNED(addr))
+ return -EINVAL;
+
+ mem_convert_secure(PHYS_PFN(__pa(addr)), numpages);
+
+ return 0;
+}
+
+int set_memory_decrypted(unsigned long addr, int numpages)
+{
+ if (!PAGE_ALIGNED(addr))
+ return -EINVAL;
+
+ mem_convert_shared(PHYS_PFN(__pa(addr)), numpages);
+
+ return 0;
+}